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author | Davidlohr Bueso <davidlohr.bueso@hp.com> | 2013-09-12 01:26:21 +0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-10-18 18:45:47 +0400 |
commit | 00c88e695ae4c001495d6768d6c91603f34aa6c7 (patch) | |
tree | 99ae5da20df535f159162b35adf5e4843e67ba0c | |
parent | c29c40392a01b9414b02c1b57b042950704cb774 (diff) | |
download | linux-00c88e695ae4c001495d6768d6c91603f34aa6c7.tar.xz |
ipc,shm: shorten critical region for shmctl
commit 2caacaa82a51b78fc0c800e206473874094287ed upstream.
With the *_INFO, *_STAT, IPC_RMID and IPC_SET commands already optimized,
deal with the remaining SHM_LOCK and SHM_UNLOCK commands. Take the
shm_perm lock after doing the initial auditing and security checks. The
rest of the logic remains unchanged.
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | ipc/shm.c | 49 |
1 files changed, 25 insertions, 24 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index 8fd9ab38e766..a204d0bfb147 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -940,10 +940,8 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) int err, version; struct ipc_namespace *ns; - if (cmd < 0 || shmid < 0) { - err = -EINVAL; - goto out; - } + if (cmd < 0 || shmid < 0) + return -EINVAL; version = ipc_parse_version(&cmd); ns = current->nsproxy->ipc_ns; @@ -954,36 +952,40 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) case SHM_STAT: case IPC_STAT: return shmctl_nolock(ns, shmid, cmd, version, buf); + case IPC_RMID: + case IPC_SET: + return shmctl_down(ns, shmid, cmd, buf, version); case SHM_LOCK: case SHM_UNLOCK: { struct file *shm_file; - shp = shm_lock_check(ns, shmid); + rcu_read_lock(); + shp = shm_obtain_object_check(ns, shmid); if (IS_ERR(shp)) { err = PTR_ERR(shp); - goto out; + goto out_unlock1; } audit_ipc_obj(&(shp->shm_perm)); + err = security_shm_shmctl(shp, cmd); + if (err) + goto out_unlock1; + ipc_lock_object(&shp->shm_perm); if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) { kuid_t euid = current_euid(); err = -EPERM; if (!uid_eq(euid, shp->shm_perm.uid) && !uid_eq(euid, shp->shm_perm.cuid)) - goto out_unlock; + goto out_unlock0; if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) - goto out_unlock; + goto out_unlock0; } - err = security_shm_shmctl(shp, cmd); - if (err) - goto out_unlock; - shm_file = shp->shm_file; if (is_file_hugepages(shm_file)) - goto out_unlock; + goto out_unlock0; if (cmd == SHM_LOCK) { struct user_struct *user = current_user(); @@ -992,32 +994,31 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) shp->shm_perm.mode |= SHM_LOCKED; shp->mlock_user = user; } - goto out_unlock; + goto out_unlock0; } /* SHM_UNLOCK */ if (!(shp->shm_perm.mode & SHM_LOCKED)) - goto out_unlock; + goto out_unlock0; shmem_lock(shm_file, 0, shp->mlock_user); shp->shm_perm.mode &= ~SHM_LOCKED; shp->mlock_user = NULL; get_file(shm_file); - shm_unlock(shp); + ipc_unlock_object(&shp->shm_perm); + rcu_read_unlock(); shmem_unlock_mapping(shm_file->f_mapping); + fput(shm_file); - goto out; - } - case IPC_RMID: - case IPC_SET: - err = shmctl_down(ns, shmid, cmd, buf, version); return err; + } default: return -EINVAL; } -out_unlock: - shm_unlock(shp); -out: +out_unlock0: + ipc_unlock_object(&shp->shm_perm); +out_unlock1: + rcu_read_unlock(); return err; } |